1. Field of the Invention
The present invention relates to a lock construction which is mounted on a door lock and operated by insertion of a key, and more particularly, to an exchangeable lock construction capable of being assembled to and disassembled from the door lock, thereby effectively preventing separation of the lock construction or unlocking of the door lock through the use of various pseudo keys, but not a correct key suitable for the lock construction, for unfair purpose.
2. Background of the Related Art
Recently, various countermeasures have been taken to prevent unlocking of a door lock for the purpose of criminal acts. As one of them, a lock construction mounted on a door lock is assemblable and disassemblable by an exchangeable key. For example, in case of a door lock for a lodging house, there occasionally occurs a case where a lodger copies a key during lodging, and then, opens the door lock of the corresponding room using the copied key after leaving the lodging house for the purpose of criminal acts. Therefore, to prevent the crime, an owner of the lodging house mounts a door lock with a separable lock construction, and then, exchanges the lock construction with another lock construction of different lodging room, if necessary.
However, the above lock construction cannot prevent unlocking by means of pseudo keys for unlocking a lock (keys that a key mechanic uses for unlocking a lock by controlling the inner pins one by one without a correct key to open a door if a user lost the correct key, but they are occasionally used for the purpose of crime), but not the copied key.
Meanwhile, there is another countermeasure that has been taken to prevent illegal unlocking of the door lock. That is, a general lock construction, which cannot be separated from the door lock, includes a side waved portion formed on a side of a key to reinforce security, and a slide bar for rotating an inner rolling body or preventing the rotation of the inner rolling body by the side waved portion.
As an example of the above lock construction, there is disclosed U.S. Pat. No. 6,477,876 in which as shown in FIG. 6, a side waved portion 101 is formed on a side of a key 100, a plurality of rectangular slide pins 120 are mounted in an inner rolling body 110, the rectangular slide pins formed at one side with grooves 121 horizontally arranged by the side waved portion 101, and a slide bar 130 is centrally pushed when the inner rolling body 110 is rotated by the arrangement of the grooves 121.
Therefore, such a lock construction can be unlocked only when an upper waved portion 102 of the key 100 aligns associated elements of the lock construction and the side waved portion 101 of the key 100 also aligns other associated elements of the lock construction, and hence can further increase security as compared with a general lock construction.
There has been an attempt to apply the security reinforcing structure by virtue of the slide bar to a door lock with an exchangeable lock construction. However, for an exchangeable lock structure (structure in which a tubular operation body is locked to the inner periphery of a fixed body or unlocked from the inner periphery while being rotated when a key is inserted and turned) by virtue of an tubular operation body among various constitutional means for exchanging the locking construction, because the tubular operation body surrounds the rolling body, the slide bar cannot be mounted. As a result, the exchangeable lock construction with the tubular operation body is weaker in security than other exchangeable lock constructions.
The present invention is aimed at combining the exchangeable lock construction using the tubular operation body with a structure in which the slide bar is operated by a side waved portion of a key, so as to further reinforce security and reliability of such an exchangeable lock construction. Furthermore, the present invention is aimed at reinforcing security by virtue of operation of the slide bar and preventing damage of the lock construction by means of a drilling machine.